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Two types of biomass adsorbents have been developed in this study using Palm Kernel Shell Activated Carbon (PKS-AC), iron oxide, and zeolite. Micrographs and the adsorbent’s chemical composition were identified using a scanning electron microscopy with a energy-dispersive X-ray (SEM-EDX), and a Brunauer–Emmett–Teller analysis was used to determine the specific surface area of the adsorbents. The newly developed adsorbents have been used for the adsorption of Palm Oil Mill Effluent (POME). The effects of adsorbent dosage, contact time, and initial solution pH were identified using Design of Experiment. The Iron Oxide Palm Kernel Shell Activated Carbon (Fe/PKS-AC) shows the highest color removal efficiency (93.2 percent) compared to Zeolite Iron Oxide Palm Kernel Shell Activated Carbon (Zeolite-Fe/PKS-AC) using 5 g/L of adsorbent dosage, an initial pH of 3 and a retention time of 40 min and 60 min, respectively. Besides, Zeolite-Fe/PKS-AC reported higher degradation efficiency (62.6%) than Fe/PKS-AC within an hour of contact time. The reusability study also shows that Zeolite-Fe/PKS-AC could retain its adsorbent capability over five cycles and had a minimal decrease of 5.6 %. It can be deduced that the newly developed biomass adsorbents from palm kernel shells can provide a cost-effective alternative for the treatment of POME and other recalcitrant wastewaters.

This study aimed to develop Refuse Derived Fuel (RDF) with high Calorific Value (CV) from mixed hazardous wastes and biomass. The potential utilization of newly developed RDF in cement production as a fuel substitute for coal has been investigated. In this work, five types of mixed hazardous industrial wastes (rubber waste, mixed waste, paint sludge, palm oil sludge and wastewater treatment plant sludge) and three biomass types (sawdust, paddy husk and empty fruit bunch) have been used. The newly developed RDF developed in this study has a CV of approximately 18,652 kJ/kg, and its volatile matter, fixed carbon and ash content of 32 %, 40 % and 28 %, respectively. The study is revealed that substituting 5 ton/hour of RDF in the coal only emits about 301 mg/m3 of NOx, which is within the regulatory limits in Malaysia. Besides, the emission of heavy metals, including Zinc, Arsenic, Lead, Copper, Antimony, and Chromium, was also within the regulatory limits. RDF in cement manufacturing kilns is economically and environmentally attractive, as the combustion of RDF allows for a reduction of about 2.25 kg of CO2 per kg compared to coal. In terms of the efficiency of clinker and stack gas emission values, the substitution of 15 % of RDF to the coal at a feeding rate of 5 ton per hour in cement production did not cause any processing and quality issues in the existing cement production process. The result revealed that substituting 15 % of RDF with the coal in 5000 ton/day cement plant may reduce 112.8 USD/hour in operating cost. Additionally, 140 USD/hour of net saving could be achieved by saving 2.52 ton/hour of CO2 emitted from the cement production. Overall, the results concluded that RDF is a very promising resource recovery and waste treatment option for hazardous waste management.

A multiresidue method without cleanup step was validated for simultaneous determination of multiclass pesticide residues in rice. The extracted incurred residues of pesticides were separated on a reversed-phase column and quantified by tandem mass spectrometry (MS/MS). The method accuracy was in the range of 71–108%, and the precision was in the range of 4–20% for 25 out of 28 selected pesticides. The method quantification limits for 25 selected pesticides were below Codex and EU maximum residue limits (MRL). The selected 25 pesticides met the EU-SANTE and FAO/WHO Codex Alimentarius Commission method validation guidelines. The interday repeatability of the optimized method was between 4 and 18% (n = 6). The expanded uncertainty calculated for the optimized method ranged from 22 to 48%. The results obtained demonstrated the method's suitability for routine analysis. In total, 35 samples were analyzed of which, 22 samples (62%) were found to be contaminated with pesticides concentrations ranging from 0.010 to 0.297 mgkg−1.

Although the macroinvertebrates have been widely used as bio-indicator for river water quality assessment in developed countries, its application is new in Iran and data on the health status of the most ecologically important rivers in Iran is scarce. The present study aimed at monitoring and assessing the ecological quality of Aghlagan river, northwest of Iran, using integrated physicochemical-biological approaches. A total of 14,423 samplings were carried out from the headwater to downstream sites at four stations (S1, 2, 3, 4) by a Surber sampler (30 cm × 30 cm) from June 2018 to April 2019. The results obtained from macroinvertebrate biotic index revealed that the genera of Gammarus (Amphipoda) and Baetis (Ephemeroptera) were the most abundant in all seasons. The PAST software was applied to analyze the diversity indices (Shannon-Weiner diversity, Evenness, and Simpson indices). Based on the cluster analysis, S3 established the least similarity to other stations. The average frequency of each macroinvertebrate species was determined by one-factor analysis of similarities (ANOSIM). In accordance with canonical correspondence analysis (CCA), temperature and phosphate were found as the dominant factors effecting the macroinvertebrate assemblage and distribution. Moreover, the results obtained from the biological indices concluded very good quality of S4 by Helsinhoff and EPT indices and fair quality using BMWP index. The data on the macrobenthos assemblage and dynamics in the Aghlagan river across a hydraulic gradient provided useful information on water management efforts that assist us to find sustainable solutions for the enhanced quality of the river by balancing environmental and human values.

Kitchen wastewater that is discharged to the environment is one of the contributing factors to water pollution in developing countries. Adsorption is one of the emerging technology of biological treatments that is an environmentally friendly for the removal of pollutants. Banana trunk fiber with chitosan as an adsorbent was investigated for minimizing COD and ammonia from the kitchen wastewater. The raw kitchen wastewater sample used in the study was collected from the Arked food court located in Universiti Tun Hussein Onn Malaysia in Johor (Malaysia). The optimum of ratio, pH, shaking speed and contact time for COD and ammonia removal were determined. The result indicated the optimum mix ratio of fiber with chitosan, pH, shaking speed and contact time respectively was 50:50, pH 7, 125 rpm and 120 minutes based on the adsorption of COD (87%) and ammonia (90%) by banana trunk fiber with chitosan. Kinetic study of the results gave a pseudo-second order the R2 was closed to unity which was 0.998. It will significantly be considered for efficient removal of organic and nutrient pollutants present in kitchen wastewater treatment.

This study investigated the potential of palm kernel shell (PKS) as a biomass feed for adsorbent production. This work aims at synthesizing green adsorbent from activated PKS by integrating iron oxide and zeolite. The newly developed adsorbents, zeolite-Fe/AC and Fe/AC, were analyzed for surface area, chemical composition, magnetic properties, crystallinity, and stability. The adsorbent efficiency in removing effluent from the palm oil mill was evaluated. The influence of operating parameters, including adsorbent dosage, H2O2, reaction time, and initial solution pH for adsorption performance was studied. The Fourier transform infrared analysis revealed that the adsorbents contain functional groups including OH, N–H, CO and CC, which are essential for removing pollutants. The SEM-EDX analysis shows holes in the adsorbent surface and that it is smooth. The adsorption study revealed that under optimized conditions, by using 4 g L−1 of adsorbent and 67.7 mM H2O2, zeolite-Fe/AC was able to remove 83.1% colour and 67.2% COD within 30 min. However, Fe/AC requires 5 g L−1 of adsorbent and 87.7 mM to remove 86.8 percent and 65.6 percent, respectively. This study also showed that zeolite-Fe/AC has higher reusability compared to Fe/AC. Among Freundlich and Temkin models, the experimental data were found to be best fitted with the Langmuir isotherm model. The kinetic analysis revealed that for both adsorbents, the adsorption process fitted the pseudo-second-order model (R2 = 0.9724). The finding reflects monolayer adsorption of zeolite-Fe/AC and Fe/AC. This study thus demonstrates the applicability of low-cost green adsorbents produced from PKS to treat oil refinery effluent and other recalcitrant wastewaters.

To date, there is no standardized Fusarium bioassay protocol established owing partly to the wide variety of Fusarium oxysporum f. sp. cubense (Foc) isolates and banana cultivars present. Thus, validation of the infection parameters is deemed essential prior to each bioassay experiment. In the current study, a simple standardized workflow was developed based on available assays for testing Fusarium wilt disease response in Musa acuminata using M. acuminata cv. ‘Berangan’ of tissue-culture origin as a model. The phenotypic assays were able to detect external disease symptoms less than one week post-inoculation, while the molecular approach using RT-qPCR identified differential expression of catalase (CAT), pathogenesis-related 10 (PR10), phenylalanine ammonia-lyase (PAL) and xylanase (XYL) genes as early as day 0. The transcript levels of PR10 and XYL fluctuated over 4 days of Foc Race 4 (FocR4 C1 HIR isolate) infection while the expression of CAT steadily increased over time. In contrast, PAL was highly upregulated at 2 days post-inoculation. These signature changes suggest that all genes tested might be involved in the early defense response of ‘Berangan’ plants against FocR4 infection. ‘Berangan’ cultivar was found to be highly susceptible to Foc Race 4 (C1 HIR isolate) with leaf symptoms index (LSI) and rhizome discoloration index (RDI) scores of 4.257 and 5.971, respectively. The procedure elaborated in this study can be used as a reference Foc bioassay for reproducible and comparable results possibly across cultivars and test isolates due to its simple steps aided by integration of phenotypic and molecular approach.

Chitosan-magnetic-graphene oxide (CMGO) nanocomposite was prepared for arsenic adsorption. The nanocomposite was characterized through BET, FTIR, FESEM, EDX, and VSM analyses. These characterizations confirmed the formation of CMGO nanocomposites with high specific surface area (152.38 m2/g) and excellent saturation magnetization (49.30 emu/g). Batch adsorption experiments were conducted to evaluate the performance of the nanocomposite in the adsorption of arsenic from aqueous solution. The effects of operational parameters, adsorption kinetic, equilibrium isotherm and thermodynamics were evaluated. The removal efficiency of arsenic increased with increasing adsorbent dosage and contact time. However, the effect of pH followed a different pattern, with the removal efficiency increasing from acidic to neutral pH, and then decreasing at alkaline conditions. The highest adsorption capacity (45 mg/g) and removal efficiency (61%) were obtained at pH 7.3. The adsorption kinetic followed a pseudo-second-order kinetic model. The analysis of adsorption isotherm shows that the adsorption data fitted well to Langmuir isotherm model, indicating a homogeneous process. Thermodynamic analysis shows that the adsorption of As(III) is exothermic and spontaneous. The superparamagnetic properties of the nanocomposite enabled the separation and recovery of the nanoparticles using an external magnetic field. Thus, the developed nanocomposite has a potential for arsenic remediation.

The present study investigates the effects of impeller design and dispersed phase volume ratio on mean drop sizes (d32) in immiscible liquid-liquid stirred vessel through experimental and modeling approaches. Various impeller designs including conventional and new impeller designs were employed to cover both radial and axial flow impellers. The microscopic method associated with image processing tools was used for the drop size analysis. The results showed the hydrofoil impeller produced the largest drop sizes while the double-curved blade turbine produced the smallest drop sizes, corresponding to about 37% difference. Increasing the dispersed phase volume ratio from 1% to 10%) increased the d32 by approximately 20–40%. Adaptive neuro-fuzzy inference system based on fuzzy C–means (ANFIS-FCM) clustering algorithm was used to develop a model to predict drop sizes, and its validation and accuracy were examined by comparing the results to the experimental data. The results also proved the superior prediction capability of the ANFIS-FCM method over the empirical correlations for the most cases.

A multi-residue method using selected ion monitoring mode GC-MSD has been developed for the quantitative analysis of 30 widely used pesticides in fresh peaches produced in Swat Malakand, Pakistan. ...

Fenton oxidation is an effective technology for the degradation of recalcitrant organic pollutants. However, conventional Fenton oxidation possesses some drawbacks such as the requirement of acidic pH condition, production of iron sludge and requirement of high chemical inputs. Strategies such as heterogeneous Fenton, fluidized bed Fenton, use of chelating agents and in-situ production of Fenton’s reagent have been studied as possible solutions to these limitations. Although there have been reviews on the fundamentals and applications of Fenton oxidation, a review with focus on the limitations of Fenton oxidation and their possible solutions is lacking. Here, we review the limitations of Fenton oxidation and the recent strategies toward addressing them. For each approach, fundamentals and applications in the removal of recalcitrant pollutants are reviewed. Heterogeneous Fenton process is the most widely investigated due to the progress in catalysis. Fluidized bed Fenton process could lower sludge generation and enhance process performance. Chelating agents are used to conduct homogeneous Fenton at circumneutral pH, though the potential detrimental effect of some chelating agents remains a source of concern. In situ production of Fenton’s reagent through bioelectrochemical technology (bioelectro-Fenton) is emerging as a possible strategy to reduce the cost associated with Fenton’s reagent.

The interaction of carriers (SiO2) and Fenton’s reagent during the degradation of recalcitrant pollutant by fluidized-bed Fenton process was investigated. Reactive Black 5 (RB5) was selected as a model pollutant since dyes are recalcitrant to conventional treatment technologies. Quantum chemical simulation and experimental approach were employed to predict the potential interactions among the chemical species involved in the process. Quantum chemical parameters such as highest occupied molecular orbital (HOMO) energy, lowest unoccupied molecular orbital (LUMO) energy, HOMO–LUMO energy gaps were computed and analyzed. Response surface methodology was utilized to investigate the effect of operational parameters and optimize the process performance. The analysis of quantum chemical parameters shows that with a comparatively higher EHOMO of − 8.72 eV, SiO2 can interact with Fe3+ (EHOMO = − 18.74 eV), which explains the crystallization of iron oxide on the carriers. The higher EHOMO–LUMO energy gap value of SiO2 (7.92 eV) indicates its potential interaction with Fe2+, Fe3+ and RB5 due to their lower EHOMO–LUMO energy gaps. RB5 exhibited the lowest hardness value (1.23 eV), indicating that it can be degraded by the hydroxyl radical (2.11 eV). For the experimental part, the process can remove up to 80% and 99.94% of the initial COD and color, respectively, under optimum conditions. The most significant parameters affecting the process performance are [Fe2+] and [Dye]. This study has provided insights into the potential interactions occurring in fluidized-bed Fenton process. The results will be useful toward optimization and scale-up of fluidized-bed Fenton process.

Hydrogen peroxide (H2O2) is commercially produced by catalytic oxidation of anthrahydroquinone, which is energy-intensive. Electrochemical production of hydrogen peroxide production through oxygen reduction reaction (ORR) is a sustainable approach, primarily due to its significance in energy conversion systems such as fuel cells. Low temperature fuel cells use graphite as a cathode for H2O2 synthesis. However, the catalytic activity of a graphite cathode for a two-electron oxygen reduction reaction must be improved. Nitrogen doping is an efficient approach to modify the electrochemically active surface of the graphite cathode. Therefore, quantum chemical approaches are essential to comprehend the molecular nature of the processes at the cathode. DFT/B3LYP/6-31G* method was employed and bond dissociation energy (BDE) analysis was performed to determine the feasibility of H2O2 production at graphite and nitrogen-doped graphite (Graphite-N) cathodes. According to the suggested mechanism, oxygen adsorption is the first step of the ORR. Calculated values showed that with energy value of 23.50 kcal/mol oxygen adsorption at the Graphite-N cathode is energetically more favorable than the graphite cathode (Ead = 65.08 kcal/mol). Considering the ORR mechanism, a second-electron oxygen reduction is identified as a key step for both H2O and H2O2 production. Therefore, BDEs were compared at the second-electron oxygen reduction step. On average, − 320.92 and − 286.04 kcal/mol of BDEs for graphite and Graphite-N cathodes showed the feasibility of H2O2 production at the Graphite-N cathode. The results are in agreement with the literature. Thus, it is concluded that nitrogen doping of the graphite cathode increases the feasibility of H2O2 production.

The presence of recalcitrant organic pollutants in water is a major source of concern worldwide. These pollutants are not easily removed using conventional treatment technologies. Integrating adsorption with advanced oxidation processes is an effective technology for removing recalcitrant pollutants. Here, we review the synergy of adsorption and advanced oxidation processes. We discuss adsorption–Fenton, adsorption–photocatalysis, ultrasound–adsorption and adsorption–Ozonation. We note an increasing use of composites with dual functions as adsorbents and catalysts in photocatalysis and heterogeneous Fenton oxidation. Ultrasound irradiation is combined with adsorption to enhance mass transfer through cavitation. However, the contribution of cavitation-induced radicals has not been quantified. While previous studies have given more emphasis on the synergy of the combined processes in pollutants removal, we have highlighted here the potential of the oxidation processes to regenerate spent adsorbents.

For every ton of biodiesel produced, about 100 kg of glycerol is also generated as a by-product. The traditional method of removing glycerol is mainly by gravity separation or centrifugation. This method generates crude glycerol, which may still contain impurities such as methanol, oil, soap, salt, and other organic materials at ppm levels. The effective usage of crude glycerol is important to improve the economic sustainability of the biodiesel industry while reducing the environmental impacts caused by the generated waste. The application and value of crude glycerol can be enhanced if these impurities are removed or minimized. Thus, it is important to develop a method which can increase the economic and applicable value of crude glycerol. Therefore, in the present study, the dual step purification method comprised of acidification and ion exchange techniques has been used to purify the crude glycerol and convert it into higher-value products. The acidification process started with the pH adjustment of the crude glycerol, using phosphoric acid to convert soap into fatty acid and salts. Then, the pretreated glycerol was further purified by ion exchange with a strong cation H+ resin. Gas chromatography (GC) was used to analyze both crude and purified glycerol and expressed as the weight percentage of glycerol content. A maximum glycerol purity of 98.2% was obtained after the dual step purification method at the optimized conditions of 60% of solvent, the flow rate of 15 mL/min and 40 g of resin. Further, the glycerol content measured being within the accepted amount of BS 2621:1979. Therefore, this study has proven that the proposed crude glycerol purification process is effective in improving the glycerol purity and could enhance the applicability of glycerol in producing value-added products which bring new revenue to the biodiesel industry.

A visible light responsive photocatalyst, nano-sized copper doped TiO2/ZnO, was synthesized by sol gel method. It was characterized in terms of thermal stability, crystalline phase, crystal size, morphology, surface area, UV–Vis DRS and band gap. The results showed that the synergistic effect of copper ions considerably narrowed the band gap of the synthesized photocatalyst compared to TiO2/ZnO. Its photoactivity was then evaluated by measuring degradation efficiency of methyl orange (MO) and methylene blue (MB) in terms of colour, COD and TOC removal. The synergistic or antagonistic effects of different combinations of dye and catalyst concentrations, pH, intensity of light irradiation and reaction time on photoactivity of Cu-TiO2/ZnO were also investigated. The highest photoactivity achieved was 85.45% of colour, 70.56% of COD and 48.70% of TOC removal for MO and 73.20% of colour, 59.92% of COD and 38.77% of TOC removal for MB under optimal conditions.

Oxidative treatment of a cationic dye solution, methylene blue, was investigated using magnetite nanoparticles and goethite in heterogeneous Fenton-like reaction, and ferrous ions in homogeneous Fenton-reaction. The aim was to compare the degradation efficiencies of the studied catalysts for decolorization of methylene blue solution as the model organic pollutant. Response surface methodology (RSM) was applied to determine the optimal operational conditions for magnetite/H2O2 and goethite/H2O2 systems. The [H2O2] of 0.2 M, catalyst dosage of 1 g/L, pH 9.0 and reaction time of 5h were chosen by RSM. The pH value of 3.0 was used in the case of Fe+2/H2O2 system. The experimental results showed that homogeneous Fenton oxidation system was the most effective system under both acidic and neutral conditions but decreased at pH value of 9.0 due to the decrease in available Fe2+ ions in the solution and generation of ferric hydroxide sludge. Fe3O4/H2O2 system represented better removal efficiency than FeO(OH)/H2O2 system that could be attributed to the presence of FeII cations in magnetite structure and its larger surface area.

Cu–ZnO/TiO2 nanoparticles were prepared by entrapping copper ions into crystalline matrix of ZnO/TiO2 through sol–gel synthesis method. The photocatalyst matrix loaded with different copper concentrations was calcined at 500 and 700 °C. Thermal property, crystalline structure, surface morphology and absorption spectra of Cu–ZnO/TiO2 were characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, transmission electron microscope and UV–Vis spectrophotometry. Besides, its specific surface area and band gap energy level were estimated through BET surface area method, Kubelka–Munk model and Planck’s equation. The results revealed that Cu–ZnO/TiO2 had a more thermally stable lattice compared to TiO2/ZnO and hence the phase transformation from anatase to rutile is retarded under higher calcination temperature in Cu–ZnO/TiO2 lattice. The photoactivity of Cu–ZnO/TiO2 was then evaluated through degradation of methyl orange under visible light irradiation. Among different samples, the samples that were calcined at 500 °C exhibited the highest photocactivity compared to those calcined at 700 °C. Cu–ZnO/TiO2 with a Cu content of 3 wt% was observed to have the maximum activity, giving C/C0 value of 0.03 after 150 min. This value was about 12 and 28.3 times higher than that of ZnO/TiO2 and TiO2, respectively.

Micro-peat (M-P) was demonstrated in the present study as a potential low cost natural adsorbent for the removal of COD and ammoniacal nitrogen (NH3-N) from landfill leachate. A series of batch experiments were carried out under fixed conditions and the influence of mixture ratio was investigated. The characteristics of leachate were then determined. Results indicated that leachate is non-biodegradable with high concentration of COD (2739.06 mg/L), NH3-N (1765.34 mg/L) and BOD5/COD ratio (0.09). The optimum ratio for activated carbon (AC) and M-P in the removal of COD and NH3-N obtained were at 2.5:1.5 (87%) and 1.0:3.0 (65%) respectively. The low-cost natural adsorbent used in the present investigation is an attractive alternative to the conventional adsorbent (AC). Thus, M-P can be appropriated for use in leachate treatment that could be cost-effective due its local availability and adsorption property.

Backgrounds: People in Yemen and in East African countries chew khat more than five hours daily. Objectives: The aim of this study was to assess the relationship between khat and occlusal caries progression. Methods: A cohort study was carried out among 98 Yemeni khat chewers and 101 non-chewers aged 18-35 years old with early occlusal caries lesions. All participants answered questions on socio-demographic, khat , oral hygiene , sugar intake, and oral health knowledge at baseline. All posterior teeth with an early enamel lesion on occlusal surfaces detected by visual inspection at baseline were also subjected to DIAGNOdent assessment to confirm early lesion (DIAGNOdent reading 13-24). Participants were re-examined after 12 weeks. Caries progression was considered to occur when the DIAGNOdent reading was >25. Data were analyzed using Relative risk, Mann–Whitney U test, a Wilcoxon Signed-Rank test and logistic regression analysis. Results: Occlusal caries progression incidence between khat chewers and non-chewers, with the relative risk was 1.68. There was no significant difference in occlusal caries progression on chewing side and non-chewing side among khat chewers. Khat chewing was a statistical predictor for those with low income. Conclusion: Khat is a risk factor for occlusion caries progression among low income group. Keywords: Khat, caries progression, DIAGNOdent pen.

The potential of Empty Fruit Bunch obtained from palm oil tree as a low-cost adsorbent is a sustainable approach in wastewater treatment. The objective this study to investigate the capability of EFB for removal colour from natural rubber wastewater as well as the influence of adsorbent dosage, pH, shaking speed and contact time. The results of the analysis show that all selected factors exhibit significant effect on removal of colour. Maximum removal (87.1%) for colour was achieved at 3.5 g of adsorbent dosage, pH 7, 150 rpm of shaking speed, 120 min of contact time. The Langmuir isotherm (R2= 0.9913) described colour adsorption slightly better than the Freundlich isotherm (R2= 0.9805), suggesting a monolayer adsorption behavior of the adsorption processes

The main problem of landfill leachate is its diverse composition comprising many persistent organic pollutants which must be removed before being discharge into the environment. This study investigated the treatment of raw landfill leachate using electrocoagulation process. An electrocoagulation system was designed with iron as both the anode and cathode. The effects of inter-electrode distance, initial pH and electrolyte concentration on colour and COD removals were investigated. All these factors were found to have significant effects on the colour removal. On the other hand, electrolyte concentration was the most significant parameter affecting the COD removal. Numerical optimization was also conducted to obtain the optimum process performance. Under optimum conditions (initial pH: 7.73, inter-electrode distance: 1.16 cm, and electrolyte concentration (NaCl): 2.00 g/L), the process could remove up to 82.7% colour and 45.1% COD. The process can be applied as a pre-treatment for raw leachates before applying other appropriate treatment technologies.

A microbial fuel cell (MFC) is a sustainable technology which commonly uses graphite as cathode for the production of hydrogen peroxide. Besides, water formation through four-electron oxygen reduction mechanism is a commonly observed product. Determining the selectivity of H2O2/H2O reaction through experimental means is time consuming because of the slow kinetics of oxygen reduction reaction. Therefore, quantum chemical approaches are essential to comprehend the molecular nature of this process. Thus, density functional theory (DFT) was employed and quantum chemical calculations were performed to predict the chemical reactivity, stability, and thermodynamic properties of molecules participating in oxygen reduction reaction at graphite cathode. The calculations showed that graphene with higher value of “highest occupied molecular orbital” (HOMO), i.e., −4.544 eV has a higher tendency to donate electron for oxygen reduction reaction Furthermore, with an aim of predicting the most favorable conditions for H2O2 production, two different points, i.e., at the edge and middle of graphene plane were investigated. Calculated values showed that oxygen adsorption with the lowest energy requirement of 43.638 kcal/mol is energetically favorable at the edge of graphene plane. Nevertheless, oxygen complexes (O2*, HOO*, and HO*) characterized by high HOMO values −4.96, −4.37, and −4.34 eV are highly polarizable in the middle of the graphene plane. Furthermore, thermodynamic feasibility analysis showed that oxygen reduction required for hydrogen peroxide production had lower ΔG values of −90.94 (edge) and −98.44 (middle) kcal/mole than that of water synthesis (i.e., ΔG = −48.37(edge), −48.97 (middle) kcal/mole) at two-electron reduction step. Therefore, it was concluded that H2O2 which followed the lowest energy pathway would be more thermodynamically feasible compared to water synthesis. © 2017 American Institute of Chemical Engineers Environ Prog, 2017

In textile wastewater, ions such as Cl−, NO3−, SO42− added as salts (dye-enhancers), were reported to exacerbate the deactivation of TiO2 surface in aqueous media. The rate of degradation of a model cationic dye methylene blue (MB) with or without NaCl and nature of adsorbed species on pure anatase TiO2 were investigated, other factors considered were pH4 and pH10, ultraviolet light (UV). XPS analysis of samples T1–T8, shows varying values of percent atomic concentration (PAC) from fresh sample Tf. For Tf, Ti (25.88%) and O (68.07%) values were higher than in any other sample and has the least C (4.11%) with no traceable amount of N, S and Na. For the deactivated samples, in addition to basic elements Ti, O and C, there were traces of new elements, nitrogen (N) in T1 (N: 1.16%), no nitrogen or sulfur (S) in T2, in T3 (N: 3.34%, S: 0.84%), T4 (N: 3.17%, S: 1.72%), T5 (N: 1.46%), T6 (N: 1.16%), T7 (N: 3.21%, S: 0.97%) and T8 (N: 3.02%, S: 1.11%, Na: 3.02%), no Cl− was found in any sample. Shifts were observed in the XPS high resolution spectra (HRS) in C1s, O1s, Ti2p, N1s, S2p and Na1s regions. FTIR confirmed the new adsorbed species on deactivated samples (T1–T8).

We prepared a number of heterogeneous catalysts by exchanging the structural iron of magnetite with molybdenum ions. To obtain the optimum value, Mo at various concentrations was coprecipitated with iron species (Fe3−x Mo x O4, x = 0.028, 0.069, 0.13, and 0.21). Characterization revealed that all the samples had inverse spinel structure with excellent stability and magnetic properties. Higher Mo contents (x = 0.13 and 0.21) significantly improved the specific surface area of magnetite, leading to higher capacity for methylene blue (MB) adsorption. The catalytic performance of the samples for degradation of MB solution through Fenton reaction was then assessed. The Fe2.62Mo0.21O4 sample showed substantial activity, removing MB completely within 150 min. This enhanced activity is discussed based on the enlarged surface area, the role of surface Mo4+/Mo6+ redox pairs, and oxygen vacancies. Kinetic studies revealed that MB degradation by Fe3−x Mo x O4 nanoparticles in presence of H2O2 was well fit by a zeroth-order kinetics model. These results support use of such Fe3−x Mo x O4 materials as active magnetically separable heterogeneous catalysts, capable of degrading various contaminants through Fenton reaction.

Advanced oxidation process involves production of hydroxyl radical for industrial wastewater treatment. This method is based on the irradiation of UV light to photocatalysts such as TiO2 and ZnO for photodegradation of pollutant. UV light is used for irradiation in photocatalytic process because TiO2 has a high band gap energy which is around 3.2 eV. There can be shift adsorption to visible light by reducing the band gap energy to below 3.2 eV. Doped catalyst is one of the means to reduce band gap energy. Different methods are used for doped catalyst which uses transition metals and titanium dioxide. The band gap energy of three types of transition metals Fe, Cd and Co after being doped with TiO2, are around 2.88 ev, 2.97ev and 2.96 ev, respectively which are all below TiO2 energy. Some of the transition metals change the energy level to below 3.2 eV and the adsorption shifts to visible light for degradation of industrial pollutant after being doped with titanium dioxide. This paper aims at providing a deep insight into advanced oxidation processes, photocatalysts and their applications in wastewater treatment, doping processes and the effects of operational factors on photocatalytic degradation.

Microbial fuel cell is a sustainable and renewable technology which commonly uses graphite as cathode for hydrogen peroxide production. One of the limitations of using graphite cathode is the slow kinetics of oxygen reduction reaction. Nitrogen doping has been demonstrated to be an efficient approach to regulate the electronic as well as surface characteristics of graphite cathode. Therefore, in this study nitrogen doping of graphite cathode was performed to determine the feasibility of H2O2 production and energy generation in a dual chamber MFC. An integrated approach of quantum chemical calculation in combination with experimental investigation was used. Quantum chemical calculations confirmed the production of H2O2 with the lowest Gibb's free energy of −63 kcal/mol. For validation, ammonia treatment of graphite cathode was performed. The XPS analysis of doped cathode revealed the presence of Graphitic-N functionalization with overall N1s content of 2.96%. Cyclic voltammetric analysis of nitrogen doped cathode further confirmed the production of H2O2 at the peak current value of −4.0 mA and on-set potential of −0.55 V. Following CV analysis, hydrogen peroxide production experiments were performed in a dual chamber MFC. Maximum of 175 mg/L of H2O2 was obtained with simultaneous power generation of 47.61 W/m3, indicating the synergetic effect of nitrogen doped cathode. Thus, from the findings of quantum chemical evaluation and experimental investigation, it is concluded that nitrogen doping of graphite cathode is an efficient approach to improve the performance of MFC in terms of H2O2 production and power generation.

This paper examines the technical and economic feasibilities of the sequential optimization technique, i.e., Taguchi coupled with principal component analysis (PCA). Fenton oxidation with four operating parameters, such as [Dye]ini, Dye/Fe+2 (wt/wt), H2O2/Fe+2 (wt/wt), and pH, was selected as a case study. COD (%), TOC (%), and color removal efficiency were chosen as responses. Total principal component index (TPCI) values, obtained as an output of sequential optimization, were used to determine the optimized conditions for Fenton oxidation. [Dye]: 100 mg/L, Dye/Fe+2(wt/wt): 50, H2O2/Fe+2(wt/wt): 25 and pH: 3 were obtained as the optimized values. In addition, ANOVA and the interaction of factors showed that pH was the most significant factor with the percent contribution of 90.86%. Economic evaluation with simultaneous comparison with Taguchi and central composite design (CCD) showed that Taguchi coupled with PCA is the most economic and time-efficient optimization technique. In this study, experimental cost was reduced to $54/m3, which showed 95% reduction relative to CCD. Moreover, chemical consumption and experimental time were also reduced by approximately 95–97% and 68%, respectively. Thus, it can be concluded that Taguchi coupled with PCA is the most cost-effective and less-laborious way of optimizing multi-response processes such as Fenton oxidation.

Palm oil mill efluent (POME) is the major industrial waste water in Malaysia and Indonesia. The processing of (POME) before discharge is a major challenge to researchers. In this study, the adsorption experiment of zinc ion from (POME) produced from the processed palm oil as primary treatment has been investigated using coconut shell and cow bone activated carbon. Experiments were conducted at a fixed initial concentration, contact time, shaking speed and at different adsorbent dosage to obtain optimum condition for the uptake of zinc ion from POME. The coconut shell carbon exhibited better removal efficiency than the cow bone powder. The results obtained at fixed condition of pH 7, contact time of 105 minutes, shaking speed of 150 rpm showed more than 90% uptake for both adsorbents. The result of the adsorption study was further analyzed using Langmuir and BET model to determine the experimental isotherm. The result showed that equilibrium data fitted better with BET model for coconut shell carbon and better with Langmuir model for cow bone powder. The result of the adsorption experiments showed that heavy metal of zinc can be sufficiently reduced on both coconut shell carbon and the cow bone powder. The morphology of both adsorbents was observed using the scanning electron microscope (SEM), the pore sizes of the adsorbents supported the uptake of zinc ion from the raw POME.

The Fenton oxidation is rarely used industrially due to its high operating cost, large chemical consumption, excessive sludge production, and operability only within a narrow pH range. Therefore, there is a need to evaluate the Fenton oxidation to maximize its ability to degrade high-strength dye wastewater at reduced operating cost. Optimization tools are among the most commonly used tool to maximize the degradation of pollutants. The current study aims at evaluating the applicability of response surface methodology (RSM) and adaptive neuro-fuzzy inference system (ANFIS) to optimize the degradation of Remazol brilliant blue through the Fenton oxidation. The effects of four operating parameters including dye concentration, retention time, and mass ratios of Dye:Fe2+ and H2O2:Fe2+ were evaluated by applying RSM. According to the RSM results, color and chemical oxygen demand (COD) removal of 99.9% and 84%, respectively, were obtained at 120 min at the COD value of 795 mg/L, mass ratios of Dye:Fe2+ = 16, H2O...

BACKGROUND Microbial fuel cells (MFCs) offer a sustainable and energy efficient solution for in situ hydrogen peroxide (H2O2) production with simultaneous power generation. In MFCs, H2O2 is produced as a result of two-electron oxygen reduction at graphite cathode surface. However, due to poor catalytic properties of graphite cathode high yields of H2O2 are not attained. Therefore, this study investigates the feasibility of in situ H2O2 production in MFC for recalcitrant wastewater treatment. METHODOLOGY AND RESULTS In this study, a dual chamber MFC was used. A heat-treated graphite electrode was used as cathode and Nafion-117 as membrane. Cyclic voltammetric analysis was also performed to study the potential of heat-treated graphite cathode for H2O2 production. Experimentally, a maximum of 140 mg L−1 of H2O2 was produced with simultaneous power generation of 33.52 W m−3. Consequently, in situ Fenton oxidation experiments were performed and compared with conventional Fenton oxidation using a recalcitrant pollutant i.e. Acid Blue 113 dye. On average, 24% difference between the performance of the Fenton and in situ Fenton oxidation was observed while 42% reduction in the cost of process was obtained in the case of the in situ Fenton oxidation process. CONCLUSION The current study proved that MFC is a sustainable solution for in situ Fenton oxidation (followed by H2O2 production) with less requirement of H2O2. © 2017 Society of Chemical Industry

In this work, a study was conducted to estimate carbon dioxide (CO2) emission of plastic resins produced from recycled plastic wastes in a medium-sized plant in Malaysia. The feasibility of using cleaner production (CP) strategies to reduce CO2 was evaluated. For this purpose, a CP audit was conducted to quantitatively identify major entities that contributed to CO2 inside the boundary of the plant. The result showed that the plant generated 0.84 kg CO2/kg resins produced, which contributing to 1.9 million tons of overall annual CO2 generated from Malaysian plastic industry. In detail, 73.8% of the emission generated in the studied plant was contributed by electricity consumption, followed by solid waste generation (23.3%) and diesel consumption (2.3%). The value is lower than a virgin plastic resins producing plant, which has a CO2 value of 2 kg CO2/kg resins produced. After the audit, a total of four potential CP options were generated focusing on reducing energy consumption. Implementation of these options was expected to reduce CO2 generated from energy consumption by 0.11 kg CO2/kg resins produced, a reduction of about 18%. The study proved that CP strategies could be implemented to reduce CO2 of recycled-plastic resins producing plant.

One of the current challenges of wastewater treatment is the presence of recalcitrant pollutants which are difficult to remove using conventional treatment technologies. This poses a threat to environmental sustainability and hinders the efforts of many industries to adopt cleaner production through zero-discharge and subsequent wastewater reuse. Effective wastewater treatment technologies are therefore needed to address this challenge. Accordingly, the last few years have seen intensified effort to develop more effective wastewater treatment technologies. The use of fluidized bed reactor in wastewater treatment, particularly Advanced Oxidation Processes and biological treatment, represents a unique opportunity for cost-effective treatment of wastewater containing recalcitrant pollutants. Although the application of fluidized bed reactor in biological wastewater treatment is well established with many large-scale plants in existence, its application in advanced oxidation processes is mostly at laboratory-scale. For proper design, upscaling and process improvement, information on the major parameters affecting the processes is important. This paper offers an overview on the applications of fluidized bed reactor in wastewater treatment, with emphasis on the important design and operational parameters affecting its performance. The discussion covers liquid-solid and gas-liquid-solid fluidized bed reactors and their applications in advanced oxidation processes, biological as well as adsorption processes which are effective wastewater treatment technologies. Fluidized bed reactors are excellent contacting devices and have the potential to enhance the effectiveness and energy efficiency of these treatment processes if properly design and utilized. An energy efficient and cost-effective wastewater treatment technology is crucial to industries adopting cleaner production. Important parameters such as reactor geometry, aspect ratio, support materials, reactor internal, superficial fluid velocity and other operational parameters are reviewed. The review concluded with some perspectives on future research interests.

This paper aims at investigating the influence of acoustic streaming induced by low-frequency (24 kHz) ultrasound irradiation on mass transfer in a two-phase system. The main objective is to discuss the possible mass transfer improvements under ultrasound irradiation. Three analyses were conducted: i) experimental analysis of mass transfer under ultrasound irradiation; ii) comparative analysis between the results of the ultrasound assisted mass transfer with that obtained from mechanically stirring; and iii) computational analysis of the systems using 3D CFD simulation. In the experimental part, the interactive effects of liquid rheological properties, ultrasound power and superficial gas velocity on mass transfer were investigated in two different sonicators. The results were then compared with that of mechanical stirring. In the computational part, the results were illustrated as a function of acoustic streaming behaviour, fluid flow pattern, gas/liquid volume fraction and turbulence in the two-phase system and finally the mass transfer coefficient was specified. It was found that additional turbulence created by ultrasound played the most important role on intensifying the mass transfer phenomena compared to that in stirred vessel. Furthermore, long residence time which depends on geometrical parameters is another key for mass transfer. The results obtained in the present study would help researchers understand the role of ultrasound as an energy source and acoustic streaming as one of the most important of ultrasound waves on intensifying gas-liquid mass transfer in a two-phase system and can be a breakthrough in the design procedure as no similar studies were found in the existing literature.

In this study, Botryococcus sp. was used to bio-remediate domestic wastewater for nutrient removal coupled with biomass production. The experiment was set up to investigate the effect of indoor and outdoor culture conditions on the efficiency of phycoremediation and potential biomass productivity, as influenced by different concentrations. The results showed that the concentration of 106 cell/mL successfully removes TP and TOC under an indoor condition at the highest efficiency of 95.4% and 85%, respectively. In addition, there was complete removal (100%) of TN in the domestic wastewater under outdoor conditions. Furthermore, most of the pseudo-first-order kinetic model for the removal of TP, TN, and TOC showed a decreasing pattern proportionate to the increase in phycoremediation time. The highest biomass productivity was also obtained at the same concentration (106 cell/mL) for the outdoor (2.6 × 105 cell/mL/d) and indoor (2.4 × 105 cell/mL/d) culture conditions. The outdoor condition provided the highest (p

This present research aims to synthesize and investigate the adsorption potential of sugarcane bagasse (SCB) impregnated with iron oxide (Fe3O4) for dye removal. The surface morphology and functional groups of the newly developed adsorbent (ISCB) were studied using Scanning Electron Microscopy/Energy-dispersive X-ray spectroscopy (SEM/EDX), Fourier transforms infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD) analysis. The effects of the operating parameters, including initial dye concentration, adsorbent dosage, contact time and initial pH of the dye solution on the adsorption efficiency were investigated to identify an optimal condition. The characterization of SEM-EDX and FTIR analyses shows that ISCB has a porous structure and carbon-containing functional groups. The adsorption result revealed that ISCB removed 93.7% of dye, 88.8% of color and had a dye adsorption capacity of 7.2 mg/g within 6 h of contact time using 0.7 g/L of ISCB at pH 8.4. The result obtained fitted well for Langmuir isotherms, and adsorption process followed the pseudo-second-order kinetic model. In conclusion, this study proved that ISCB has the potential to be used as an effective and low-cost adsorbent to remove dyes from wastewater.

There is a renewed interest in the application of chitosan-based drug delivery systems over the last few years. In this study, the ionic gelation method was used to prepare chitosan-engaged tripolyphosphate ions, as the cross-linking molecule, (Chit-TPP) and concurrent loading of the biomolecules of the ethanolic extract of fennel, Foeniculum vulgare, seed (FEC@NBC). The samples were characterized by SEM, DLS, TGA, FTIR, XRD, GC-MS, and zeta potential, and their effects on the related hormonal and biochemical factors of the rats with polycystic ovarian syndrome (PCOS) were assessed. The estradiol valerate-induced PCOS in female rats was confirmed by vaginal smear test and subsequent histological screening. The PCOS-induced rats were treated by fennel seed extract (FSX), Chit-TPP, and FEC@NBC. The process of treatment was monitored by measuring the serum levels of testosterone, luteinizing hormone, follicle-stimulating hormone, insulin, glucose, high-density lipoprotein cholesterol, total cholesterol, and total triglyceride after 16 days of treatment and compared with healthy control and untreated PCOS-control groups. The FEC@NBC administration contributed to the remarkable hormonal, glucose, and lipid profile regulation in the rats with PCOS. The significance of FEC@NBC performance in dealing with PCOS complications compared to that of the only extract could be resulted from the effective targeted delivery and stability of phytomolecules when encapsulated in Chit-TPP.

The electrocoagulation (EC) of Congo red dye-containing wastewater was investigated, focusing on the optimization of operational parameters and process mechanism. The EC was conducted using iron electrodes and utilizing Congo Red (CR) dye as a model pollutant. Response surface methodology (RSM) was used to investigate the effect of operational parameters (initial dye concentration, pH and inter-electrode distance) and optimize the process. To provide insight into the process mechanism, quantum chemical analysis and FTIR were utilized. The process achieved 89% and 97% COD and color removal respectively under optimum conditions (1000 mg/L initial dye concentration, pH 3 and 3 cm inter-electrode distance). The electrical energy required to achieve the optimum COD removal was estimated to be about 36.9 kJ. The quantum analysis showed that CR with HOMO energy of −5.58 eV and Fe3+ LUMO energy of −15.09 eV exhibit electron donating and electron accepting tendency respectively. In addition, Fe3+ shares its LUMO with the HOMO of HO– due to the lower energy gap of −19.47 eV, which leads to the formation of monomeric coagulant such as Fe(OH)3 and the subsequent polymeric flocculants including Fe2(OH)24+ and Fe6(OH)153+. The FTIR analysis of the sludge indicates the presence of coagulant species i.e. Fe(OH)3, Fe(OH)2+, Fe(OH)2+ and Fe2(OH)24+ that are generated from the EC. The findings of this study show that quantum chemical analysis and RSM are suitable for investigating the mechanism and optimization of EC as applied to textile effluents.

Microbial fuel cell (MFC) is a sustainable and energy efficient technology, which uses graphite as cathode for hydrogen peroxide (H2O2) production often with simultaneous power production. Nevertheless, slow kinetics of oxygen reduction reaction (ORR) at the surface of graphite often results in poor performance of MFC. In an attempt to improve the performance of MFC for in-situ H2O2 production, a treatment of graphite cathode using nitric acid was performed. The treatment was conducted in three steps (i) heat treatment at 450°C for 2 h; (ii) acid treatment with concentrated nitric acid for 5 h; and (iii) drying at 120°C for 2 h. After the treatment, four times increase in surface area of treated cathode (GR-HA) was observed. Energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FTIR) analysis revealed the presence of nitrogen and quinone based functional groups on the surface of GR-HA. Cyclic voltammetric (CV) analysis of GR-HA cathode further confirmed the production of H2O2 at the peak current value of −3.7 mA and on-set potential of −0.1 V. Following CV analysis, H2O2 production experiments were performed in a dual chamber MFC using GR-HA as cathode. Maximum 150 mg/L of H2O2 was produced with simultaneous power production of 36.438 mW/m2. Approximately, 25% increase in both H2O2 and power production was observed in the case of G cathode. Subsequently, Fenton oxidation experiments were performed (with GR-HA and GR-CA cathodes) to determine the efficacy of in-situ produced H2O2. This resulted in an increase of 8.28%, 11.04%, and 31.32% in decolorization, chemical oxygen demand (COD), and Total Organic Carbon (TOC) removal efficiency, respectively. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 382–393, 2017

Sonochemical reactors operate based on the release of high amount of energy from ultrasonic irradiations. More application in chemical processes are being developed using these reactors. But the potential of their applications are still limited largely due to the lack of understanding about their design, operational and performance characteristics. A detail review is therefore conducted on available literature in this paper. From the review, the design features of sonochemical reactors are defined by different types, number and position of ultrasonic transducers, whereas their operational parameters are determined by ultrasonic frequency and intensity. As in the case of stirred vessel, sonochemical reactors can be also characterized for their performance based on mass transfer, mixing time and flow pattern. The review claims that sonochemical reactors have potential to be more energy efficient compared to stirred vessel if designed and operated appropriately.

The most critical parameter of palm oil mill effluent (POME) is chemical oxygen demand (COD mg/L). The adsorption of COD mg/L from raw POME using activated cow bone powder has been investigated. The raw POME contains 4.786 g/L of COD, which has to be treated effectively before discharge. Batch experiments were conducted at fixed condition of pH, contact time and speed at different weight dosages for different particle sizes of 75, 150 and 300μm. The result obtained showed a similar adsorption pattern for the particle sizes, the optimum removal was obtained at 150 μm at 0.025g/L with 71% removal efficiency, there was no further significant diference after the adsorption at this stage. The BET adsorption model was adopted to describe the experimental isotherm and isotherm constants for the optimum particle size. The equilibrium data fitted well to the BET model. The hydrophobic behaviour of the CBP proved by the WDPT analysis influenced the removal of COD mg/L on CBP.

The current study aims at analyzing unsteady jet mixing of non-Newtonian fluids and the cavern structure in order to reduce the volume of stagnant zone in anaerobic digester tanks. The study was conducted by integrating computational analysis of the system into the experimental analysis. Accordingly, a highly viscous xanthan gum solution that mimics sludge with high solids concentrations was used to simulate municipal wastewater. Mixing was provided by a submerged, downwards-pointing and recirculating jet. Besides, a Computational Fluid Dynamics (CFD) model was developed to investigate different flow regimes, cavern formations, cavern growths, cavern volumes and the effects of rheological properties and specific power input on them. The variation in the xanthan gum rheology due to the digestion process was considered using the power law model. CFD was accomplished to investigate the hidden details of the system and experimental tests were used for validating CFD results. It was found that the bilaterally symmetrical structure of the cavern depended on the rheological properties and position of the outlet point, which directly affected the volume fraction of active/inactive zones. Accordingly, three different flow regimes for the cavern structure and the reduction trend of the inactive zone were recognized. Comparison of three different power inputs also demonstrated that reduction of inactive zones was not significantly affected by the power input beyond the optimum power input. Another key parameter was found to be the position of the outlet. It was found that active materials made more than half to 80% of the outlet while only half of the digester was filled with active materials.

Cross sensitivity due to temperature variation and the presence of other contaminants in an analyte could affect the accuracy of concentration measurement made by a sensor. In this study, a miniaturized non-adiabatic interferometer fiber optic sensor (NAIFOS) is used to monitor the Remazol Black B (RBB) dye concentration in the presence of other contaminants, pH adjustment and temperature variation. The objective of this experiment is to investigate the ability and accuracy of the sensor to monitor RBB concentration under the influence of cross-sensitivity from a single spectrum, which is considered as an advantage over traditional sensing techniques. The developed sensor shows a dye concentration sensitivity of 0.0013 nm/ppm between 0 and 800 ppm when conducted room temperature without the presence of other contaminants. The influence of pH, suspended solids in the sample and temperature variation on the accuracy of the measurement is also examined. The results show that the sensor could still provide an accurate measurement if the pH value falls between 3.07 and 10.09 with very low concentration of suspended solids (approximately 1 mg/L). In addition, a corrective measure for temperature bias is carried out by compensating the cross-sensitivity effect and a model for temperature compensation is established. To the best of our knowledge, this might well be the first attempt to establish temperature correction and compensation for optical fiber sensing using non-adiabatic tapered fiber sensor. In extended experiments involving many concentration levels, the results obtained are encouraging.

Photocatalytic reactors are not commonplace in treatment of wastewater on a commercial scale. This critical review presents a perspective on how to harness the knowledge gained in areas of mass and photon transfer limitations via photoreactor intensification processes to prolong TiO2 catalyst life for photo reactor design. The paper revealed the necessity of TiO2 rational design; considering its surface (rutile and anatase lattices), protonation, water splitting reactions at the TiO2 coordinatively unsaturated sites (CUS) as the limiting step during photocatalytic reactions adding more knowledge on surface interactions that lead to activity inhibition.

One of the most pivotal limitations of TiO 2 or ZnO based lattices is their photocatalysis activity under visible light irradiation. In this study, a hybrid photocatalyst was generated by doping TiO 2 /ZnO lattice with copper in order to improve their photo-activity. The main aim was to analyse the sensitivity of photoactivity of Cu–TiO 2 /ZnO toward operating conditions in advanced oxidation reaction for photodegradation of two different dyes under visible light irradiation. The sol–gel-prepared composite was characterized in detail to confirm its properties in terms of band gap, crystalline structure/size, optical absorption and surface area. Then, ANFIS (Adaptive Neuro Fuzzy Inference System) was employed to investigate the effects of five independent variables including dye and catalyst concentrations, pH, intensity of light irradiation and reaction time on the photocatalytic performance of Cu–TiO 2 /ZnO. This process includes several ways of discovering a subset from the group of the recorded parameters and predicting which variable has the strongest effect on the response of interest. Besides, variable search was performed using the ANFIS network. According to variable selection using ANFIS analysis, catalyst concentration and reaction time were the most effective parameters for MO degradation whereas dye concentration and pH were the most influential factors on MB removal using Cu–TiO 2 /ZnO. Furthermore, Cu–TiO 2 /ZnO photocatalyst presented the maximum removal efficiency of: color: 83.35%, COD: 73.54% and TOC: 54.46% for MO degradation and color: 75.50%, COD: 68.00% and TOC: 46.41% for MB degradation.

Iron based heterogeneous catalysts are widely used in many industrial applications including Fenton Oxidation Processes (FOPs) to treat the effluents containing recalcitrant contaminants such as dyes. In this work, Metal–Organic Framework (MOF) derived iron nano oxide particles supported on ZSM-5 zeolite were synthesized under optimized experimental conditions. The Central Composite Design (CCD) method was employed to optimize the yield of the catalyst. The catalyst was then characterized using EDX, SEM, HRTEM, FTIR, STA and BET. Subsequently, the catalytic activity of the catalyst in the Fenton oxidation process was evaluated based on the degradation of the model azo dyes Acid Blue 113, Methyl Orange, and Reactive Black. The optimized experimental yield was 81.5%, which was in agreement with the CCD prediction. Apart from high catalyst yield, excellent mineralization efficiency was obtained where 77%, 71% and 68% of Total Organic Carbon (TOC) removal were achieved for Acid Blue 113, Methyl Orange, and Reactive Black 5, respectively. Based on the yield and activity, it was concluded that the synthesized Fe-ZSM-5 is a promising catalyst for the Fenton oxidation process.

The agriculture waste material can give benefit to many production industries. The studied crop is corn (Zea Mays)stalk. The objective of this work was to analysis the chemical composition; to study chemical pulping and papermaking properties of corn stalk and; to investigate the fiber morphology of properties of those crops. Firstly, the chemical composition of corn stalk were determined and compared with other non-woods. After that, chemical corn stalk was conducted in this analysis followed the physical and mechanical properties. The result showed that, corn stalk have cellulose (39.0%) and lignin content is the lowest (7.3%) content rather than other composition. In chemical pulping, reached high pulp yields had been produced and the strength properties: tear index, tensile index, burst and fold verified that they were of an acceptable quality for papermaking. This crop morphology was observed by Scanning Electron Microscopic (SEM), which showed a condensed composition of fiber structure. This study can developed a friendly product and promote the green technology, suitable to be used as an alternative pulp in paper making industry.Keywords:Fiber, Corn stalk, Composition, Green technology, Pulp and paper making.

The batik industry is operated as a cottage industry due to variation in the designs and demand of batik. Batik is considered an art. However, the batik industry consumes a large volume of water and produces a large amount of wastewater that contains grease, resin, surfactants, wax, suspended solids and dyes. Hence, this industry requires treatment systems, which are inexpensive, simple, safe to operate, energy efficient, do not require skilled workers and do not produce secondary pollutants. In this regard, AOPs characterized by the production of highly reactive radicals, which are able to degrade most of the recalcitrant organic pollutants, have been found to fulfil the requirement. The Fenton process is one of the low-cost, low-footprint, simple and less complicated AOPs that can be used to treat effluent that has a high COD. At the optimal conditions (room temperature, undiluted contaminants), 81.4% COD, 70.5% TOC and 99.6% color removal were obtained within an hour by the Fenton process. The samples were analyzed using FTIR, GC-MS and HPLC, which confirmed the superiority of the Fenton process. The GC/MS analysis revealed that the Fenton process successfully removed 71% of organic compounds. Sludge characterization by SEM and particle size distribution showed that the Fenton generated sludge achieved suitable disposal qualities.

In this research, a milk thistle seed extract (MTSE)-rich medium was used as a capping and reducing agent for the one-pot biosynthesis of ZnO/Ag (5 wt%) nanostructure. The sample was systematically characterized through various techniques and its strong biomolecule‒metal interface structure was supported by the results. The efficacy of the derived nanostructure (MTSE/ZnO/Ag) was evaluated in vivo on the basis of its therapeutic effects on the main complications of Type 1 diabetes (hyperglycemia, hyperlipidemia, and insulin deficiency). For this purpose, the changes in the plasma values of fasting blood glucose, total cholesterol, total triglyceride, high-density lipoprotein cholesterol, and insulin in alloxan-diabetic Wistar male rats were compared with those in healthy and untreated diabetic controls after a treatment period of 16 days. The antidiabetic results of MTSE/ZnO/Ag were compared with those obtained from pristine ZnO, MTSE, and insulin therapies. The health conditions of the rats with Type 1 diabetes were significantly enhanced after treatment with MTSE/ZnO/Ag (p 0.05), which is owing to the enhanced interface structure and participatory functions of the united compartments of MTSE/ZnO/Ag.

In this work, we investigated the synergy of oxidation-adsorption and surface interaction in fluidized bed Fenton process with granular activated carbon (GAC) as carriers. Experiments were conducted to evaluate the synergy of oxidation and adsorption in the removal of a model pollutant, Reactive Black 5. The effects of carrier loading and solution pH on the process performance were investigated. To determine the nature of interaction between the carriers, Fenton’s reagent and pollutant, the surface of the GAC was analyzed using FTIR, SEM/EDX, XPS and BET analyses. The highest COD and color removal obtained were 83% and 99% respectively, at 20 g carrier loading and pH 3. More than 28% of the initial COD was removed through adsorption by the carrier. The process performance increased with increase in carrier loading but decreased when the loading exceeded a certain threshold. Although the highest COD removal was obtained at pH 3, effective removal was still achieved at pH 7. The surface analysis of the carrier reveals that both Fenton’s reagent and organic pollutant are adsorbed on the surface of the carrier, indicating that the removal of the pollutant is through both adsorption and oxidation. The performance of GAC in this study is superior to the commonly employed carrier, SiO2. This study shows that GAC can be used as an effective carrier in fluidized bed for Fenton process.